Conventional filtering of a point of interest in an image is often based on image data in a local region around the point.
For each point of interest, the local image data is read from a main buffer into the filter. Where multiple points of interest are in close proximity to each other, the same image data is commonly read from the main buffer multiple times, once for each point.
It would be desirable to minimize the number of times that the image data is access from the main buffer when filtering the entire image.